Portable mechanical ventricular assistance device

ABSTRACT

A portable mechanical ventricular assistance device including a ventricular assistor cup designed to receive the ventricles of the heart. The cup assembly is comprised of a rigid shell having a configuration generally conforming to the surface configuration of the heart ventricles and a flexible liner which is caused to contract and expand about the heart ventricles to effect the pumping action. The heart ventricles are retained within the cup by a substantially sustained negative pressure while the pumping action is produced by the application of alternating positive and negative pressure pulses to the cup. Both the sustained negative pressure and the positive and negative pressure pulses are generated by a hand pump assembly which includes a manually operable handle connected through a piston rod to a reciprocating piston mounted within the cylinder of the pump. The piston effectively divides the cylinder into two chambers, one of which is coupled through a conduit to provide the sustained negative pressure to the cup. The remaining chamber is coupled through a second conduit to the ventricle assistor cup to provide for the alternating positive and negative pressure pulses. Suitable adjustable relief valves are provided in each of the conduits to regulate the pressure levels and the positive or negative pressure directed to the cup.

United States Patent Inventor Peter Schifl RD #2. Lambertville. NJ.08530 Appl. No. 789,551 Filed Jan. 7, 1969 Patented July 6, I971PORTABLE MECHANICAL VENTRICULAR Primary Examiner-L. W. TrappAnomey0strolenk, Faber, Gerb & Soffen ABSTRACT: A portable mechanicalventricular assistance device including a ventricular assistor cupdesigned to receive the ventricles of the heart. The cup assembly iscomprised of a rigid shell having a configuration generally conformingto the surface configuration of the heart ventricles and a flexibleliner which is caused to contract and expand about the heart ventriclesto effect the pumping action. The heart ventricles are retained withinthe cup by a substantially sustained negative pressure while the pumpingaction is produced by the application of alternating positive andnegative pressure pulses to the cup. Both the sustained negativepressure and the positive and negative pressure pulses are generated bya hand pump assembly which includes a manually operable handle connectedthrough a piston rod to a reciprocating piston mounted within thecylinder of the pump. The piston effectively divides the cylinder intotwo chambers, one of which is coupled through a conduit to provide thesustained negative pressure to the cup. The remaining chamber is coupledthrough a second conduit to the ventricle assistor cup to provide forthe alternating positive and negative pressure pulses. Suitableadjustable relief valves are provided in each of the conduits toregulate the pressure levels and the positive or negative pressuredirected to the cup.

PORTABLE MECHANICAL VENTRICULAR ASSISTANCE DEVICE The present inventionrelates to circulatory sustaining devices, and more particularly to anovel portable mechanical ventricular assistance device for sustainingthe pumping action ofa heart.

Numerous devices have been developed to either sustain the circulatoryfunction of a patient, or, alternatively, to sustain the pumping actionofa heart. All such devices may be classified into two basic categories;namely, bypass systems and indirect pumping systems. Devices fallinginto the category of bypass systems are designed to bypass the flow ofblood from the heart and to maintain the pumping action otherwiseperformed by the heart through mechanical or electromechanical devices.Devices falling into the indirect pumping category are designed toassist the heart in the performance of its pumping function. The presentinvention falls into the latter category.

Devices classified in the former category are usually quite complex innature and rather large in size so as to limit their use to operatingrooms and effectively prohibit their use as a portable device.

Devices developed up to the present which are classified in the lattercategory are normally comprised of motor means for developing thenecessary pressure or vacuum levels and are further comprised ofelectromechanical means for regulating the flow of the necessarypressure levels to the heart pump. Such equipment is likewise heavy innature and large in size so as to prohibit its use as a truly portabledevice.

Devices of the indirect type have been used with great success in thefields of heart and organ transplants. When a potential cadaver (donor),whose organ or organs are available for transplant purposes, istoreceive mechanical ventricular assitance, the assistor system is rushedto him for the purpose of sustaining the heart pumping action. Underpresentday techniques and with present-day device, in order to transportthe cadaver to the operating room, the assistor is temporarilydisconnected, due to the fact that it is too bulky and requires too muchelectrical power to perform the circulatory function during the time inwhich the donor is being moved. The period during which the assistordevice is disconnected may thus have a harmful effect upon the organ ororgans to be transplanted.

The device of the present invention, which is designed to be trulyportable and to be simple to connect and operate, is extremelyadvantageous for use during the period of time in which the donor isbeing moved from one location to another, as well as for other emergencysituations.

The present invention is comprised of a ventricular assistor cupassembly having a rigid outer shell ofa configuration substantiallyconforming to the surface configuration of the heart ventricles. The cupcontains a flexible liner capable of expanding and contracting about theheart ventricles to perform assistive pumping action.

The cup is provided with a first large opening for receiving the heartventricles. A second opening provided at the apex of the cup receivesthe sustained negative pressure necessary to retain the ventricleswithin the cup assembly. A third opening provided in the cup along thesurface thereof and intermediate the first and second openings isdesigned to receive the pulsatile pressures of alternating positive andnegative pressure pulses which cause the contraction and expansion ofthe flexible liner about the heart ventricles.

All of the above-mentioned pressures are provided through the use of asingle portable pump assembly having a first handle adapted to receiveand position the operator's foot for holding the pump steady duringoperation. A second manually operable handle is provided for driving areciprocating piston mounted within the pump cylinder. The pistoneffectively divides the pump cylinder into first and second chambers,each of which is coupled through an associated conduit to the sustainednegative pressure opening and the pulsatile pressure opening,respectively. Adjustable relief valves are provided in the pulsatilepressure conduit to control the pressure (or vacuum) level of the pulseinjected into the pulsatile pressure conduit. Similar adjustable reliefvales are provided in the sustained negative pressure conduit forcontrolling the level of negative pressure and for bypassing positivepressure pulses from reaching the assistor cup assembly. An additionaloneway valve assembly is provided in the sustained negative pressureconduit to prevent positive pressure pulses from reaching the assistorcup assembly and to maintain the negative pressure developed in the cupduring the application of positive pressure pulses to the sustainednegative pressure line.

The simplicity and portability of the system make it extremelyadvantageous for use in a variety of applications, especially those ofan emergency nature. The portable system described herein may be easilyand rapidly substituted for conventional assemblies in moving donorsfrom one location to another, or may be used in emergency situations tosustain the circulatory function until such time as the patient is movedto a hospital.

It is, therefore, one object of the present invention to provide a nevelportable mechanical ventricular assistance device.

Still another object of the present invention is to provide a novel pumpassembly for use with ventricular assistor cup assemblies, and the like,which is capable of developing a sustained pressure at a first outputthereof and which is capable of developing a pulsatile pressure ofalternating positive and negative pressure pulses at the second outputthereof.

Yet a further object of the present invention is to provide a novel pumpassembly for use with ventricular assistor cup assemblies, and the like,which is capable of developing a sustained pressure at a first outputthereof and which is capable of developing a pulsatile pressure ofalternating positive and negative pressure pulses at the second outputthereof, whereby the pressure levels of the sustained and alternatingpressure pulses are made adjustable through the use of adjustable valvemeans associated with each of the hand pump outputs.

These as well as other objects of the present invention will becomeapparent when reading the accompanying description and drawings inwhich:

FIG. 1 shows a diagrammatic view partially sectionalized of the pumpassembly of the present invention as applied to a ventricular assistorcup assembly.

FIGS. 2a and 2b are schematic diagrams showing alternative embodimentsfor the pump portions of the assembly.

The device of the present invention is comprised of a hand pump assembly10 for use in operating a ventricular assistor cup assembly 20.

The ventricular assistor cup assembly is described in greater detail incopending application (M-60l9) Ser. No. 785,652, filed Dec. 20, 1968 andassigned to the assignee of the present invention, which description isincorporated herein by reference thereto. For this reason, a detaileddescription of the assistor cup assembly will be omitted from thisapplication for purposes of simplicity. For purposes of understandingthe.

present invention it is sufficient to understand that the assistor cupassembly 20 is comprised of a rigid cup 21 having a first large opening22 for receiving the ventricles of the heart; a second opening 23arranged at the apex of the cup for receiving a sustained negativepressure line; and a third opening 24 for receiving a pulsatile pressureline. The interior of the cup is provided with a flexible liner 25secured at 26 and 27 by suitable adhesive means, for example, near theapex opening 23 and the large opening 22, respectively. The liner 25 ismounted within and sealed to cup 21 in such a manner as to form a hollowinterior space whose only opening is opening 24 which receives thepulsatile pressure line. The injection of positive pressure into thishollow interior space causes the contraction of liner 25 which, in turn,contracts the ventricles of the heart embraced by the liner. Injectionof a negative pressure pulse returns the liner 25 substantially to theposition shown in FIG. 1 to allow for expansion of the heart ventricles.This operation is continuously repeated to assist the heart insustaining its pumping function. The apex opening 23 receives thesubstantially sustained negative pressure to retain the ven tricleswithin the cup throughout the entire pumping operation and independentlyof the pulsatile pressure applied to opening 24.

The portable pump assembly for use with the ventricular assistor cupassembly 20 is comprised of a cylinder 13 having secured at one exteriorend thereof a handle 12. The cylinder contains a reciprocating piston 14of the double-acting piston type. Piston 14 is coupled through a pistonrod 15 to an exterior mounted handle 11. The opening provided for pistonrod 15 at the upper end of cylinder 13 may be provided with a suitableseal such as an O-ring 16 to prevent the escape of compressed air fromthe cylinder.

Piston l4 effectively divides the cylinder into first and second pistonchambers 17 and 18.

Upper chamber 17 is provided with an opening 18 for receiving asustained negative pressure conduit 31 which couples chamber 17 througha liquid trap 32 and conduit 33 to the opening 23 provided in the apexof assistor cup 21.

Lower chamber 18 is provided with an opening 34 for receiving a conduit35 coupling the chamber to the pulsatile pressure opening 24 in cup 21.

Suitable valve means are provided in the conduits connecting theassistor cup to the pump assembly for regulating the pressure level andpressure direction of pressure pulses in jected into each of the lines.The conduit 31 is provided with a first one-way valve assembly 36 whichmay, for example, be comprised of first and second spaced annular rings37 and 38 arranged in the interior of conduit 31. A spherical member orball 39 is normally urged against annular-shaped ring 38 by a biasspring 40 secured at one end to annular disc 37 and having its oppositeend bearing against ball 39.

Similar one-way valve assemblies 41 and 46 are arranged at spacedintervals along conduit 31 to perform functions which will be more fullydescribed.

In a like manner, positive and negative relief valve assemblies 53 and58 are arranged at spaced intervals along the surface of conduit 35 forfunctions to be more fully described.

The upper piston chamber 17 provides the sustained negative pressure forthe ventricular assistor cup which is obtained on the down" stroke ofpiston 14. Let it be assumed that the piston 14 is positioned near thetop of cylinder 13 and is moved vertically downward in the directionshown by arrow A. A negative pressure or vacuum is developed in chamber17. Due to the pressure differential across the right-hand and lefthandsides of one-way valve 36, ball 39 is caused to unseal the opening inring 38, allowing this negative pressure (i.e., vacuum) state tocommunicate with the apex opening 23 in cup 21.

The relief valve assembly 46 is adjusted to cause ball 49 to unseal theopening in ring 50 when the negative pressure in conduit 31 is greaterthan a predetermined threshold level. The relief valve 46 thusautomatically controls the maximum negative pressure applied to theassistor cup. The maximum negative pressure may be made adjustable byproviding suitable means for adjusting the bias applied to ball 49 bybias spring 48. A suitable filter member 51 is secured between ring 50and-ring 52 to filter out dust or any other unwanted particles carriedby the air entering into the system when valve 46 opens.

The negative pressure applied to the assistor cup is sustained until thepiston 14 reaches the bottom of its stroke. On the up' stroke, i.e.,when the piston moves from the bottom of its stroke upward in thedirection shown by arrow B, one-way valve 36 is sealed to preventpositive pressure from passing the valve and communicating with theassistor cup. The sealing of valve 36 during the entire "up" stroke alsoacts to maintain the negative pressure in assistor cup until the nextdown" stroke. One-way valve 41 releases the pressure being developed inupper chamber 17 during the upward stroke by having its ball 42 moveddownwardly against the force of bias spring 43 to unseal the opening inannular-shaped ring 44. The negative pressure developed in conduit 31during a down" stroke of piston 14 is thus sustained during theup"stroke of piston 14. The liquid trap 32 traps any liquid passing fromcup assembly 20 toward the sustained negative conduit 31.

Lower piston chamber 18 operates in much the same manner as upperchamber 17 except that both positive and negative pulsatile pressuresare applied to cup opening 24 by line 35. For this reason, conduit 35 isprovided with two relief valves, one for positive pressure 53 and onefor negative pressure 58.

During an up" stroke of piston 14, i.e., when piston 14 moves in thedirection of arrow B, a negative pressure or vacuum is developed inconduit 35 and is coupled to cup opening 24, causing the flexible liner25 to move from a contracted position to the relaxed position shown indotted line fashion in FIG. 1. If this negative pressure exceeds apredetermined threshold level, the ball 59 of relief valve 58 will movedownward against the force of biasing spring 60 to unseal the opening inring 61, thereby automatically controlling the maximum negative pressurewhich may be developed in conduit 35.

During a down" stroke of position 14, i.e., when the piston moves fromits uppermost position downward in the direction shown by arrow A, apositive pressure is developed in lower piston chamber 18, causing apositive pressure pulse to be injected into opening 24 of theventricular cup assembly. This causes the flexible liner 25 to contractthe ventricles of the heart encircled by the liner. If the positivepressure injected into conduit 35 exceeds a predetermined thresholdlevel, ball 54 of relief valve 53 will be caused to move upwardlyagainst the force of bias spring 55 to relieve the excess positivepressure developed in conduit 35. The relief valves 53 and 58 therebyautomatically control the positive and negative pressure pulsesdelivered to thei'ventricular cup assembly 20. Suitable adjustabie meansmay be provided in both the positive and negative relief valveassemblies 53 and 58, respectively, to adjust the force of the biasingsprings an thereby calibrate the maximum positive and negative pressurelevels. The relief valves further limit the pressures as necessary forfull strokes, regardless of the ventricular cup-pumping displacement.The negative relief valve assembly is provided with a filter 63 tofilter out any unwanted particles or other material which may be in theatmosphere against entering into the system with the air enteringthrough the relief valve assembly 58 whenever it is caused to open.

The pump may be operated by one person in a variety of ways. Onepreferred manner of operating the pump is to place one foot through theopening formed by stationary handle 12 and operating the movable handle11 in a reciprocating fashion by grasping and moving handle 11 witheither one or both hands. Alternatively, each of the handles 11 and 12may be grasped by one hand, and the pump may be operated in areciprocating fashion in this manner. Obviously, if desired, two personsmay operate the pump, but the simplicity of operation and size of thepump does not necessitate such alternative operation.

FIGS. 2a and 2!) show alternative arrangements for the pump assembly ofFIG. 1. Considering FIG. 2a, the pump arrangement 10! is a bellows pumpselectively expandable and contractable due to its bellows arrangement70. The interior of the bellows arrangement is divided by a barrier wall71 forming upper and lower chambers are coupled to conduits 31 and 35 ofFIG. 1 in the same manner as the pump assembly shown in FIG. 1.Operation of the pump assembly of FIG. 2a may be performed in the samemanner as the device shown in FIG. 1 by grasping the handles 11 and 12and urging them alternatively together and apart to create the positiveand negative pressure phases occurring during each reciprocating cycle.

FlG.2b shows an alternative pump assembly having a bellows assembly 70comprised of a singleinternal chamber 72 having openings 73 and 74 forcommunicating with the conduits 31 and 35 of FIG. 1. In operation, thehandles 1] and 12 are alternately urged toward one another and apartfrom one another to create positive and negative pressures within theinternal chamber 72 to provide the positive and negative pressuresignals in conduit 35 while providing only a sustained negative pressuresignal in conduit 31.

When using the double-acting piston type of FIG. 1, it is possible todevelop sustained negative pressure in conduit 31 during both the up"and down stroke by coupling an additional conduit near the bottom ofcylinder 13 which is provided with valve'assemblies substantiallyidentical to the assemblies 36, 41 and 46. This additional conduit maybe coupled into conduit 31 as shown by dotted line 31'. Thus, eachstroke, whether up" or down, of the piston willcontribute to sustainingthe negative pressure in the assistor cup assembly. This alternativeembodiment may be used in cases where the pump assembly is capable ofproviding a sufficient negative pressure pulse for operating theflexible liner 25 and for simultaneously sustaining the negativepressure maintained at the opening 23 of the assistor cup assembly.

It can be seen from the foregoing description that the present inventionprovides a novel portable pump assembly especially advantageous for usewith ventricular assistor cup assemblies to maintain and sustain thepumping operation of the heart by providing an independent sustainednegative pressure (vacuum) at one output thereof and by providingalternating positive and negative'pressure pulses at a second outputthereof for performing the functions necessary in the operation of sucha ventricular cup assembly. It should be obvious that variousmodifications may be made in the pump assembly without departingfrom'the scope of the invention. For example, a one-way valve of thetype shown in conduit 31 may be provided in conduit 35 for providingsustained negative pressures in each of the outputs developed by thepump for such applications in which negative pressures of this typemight be required. The negative pressure values obtained may be adjustedto be of different values through simple adjustment of the valves. As afurther modification, the one-way valves provided within each of theconduits 31 and 35 may be reversed in direction of operation so as toprovide a first output for generating a positive sustained pressure anda second output for generating a sustained negative pressure. As stillanother alternative, the one-way valve assembly 36 provided in conduit31 may be omitted to provide a pump having two outputs, each of which iscapable of providing alternating positive and negative pressures whereineach of the positive and negative pressures developed by each of theoutputs may be set at any predetermined threshold levels, depending uponthe needs of the user. In addition, the single cylinder having adouble-acting piston may be replaced by two cylinders each having areciprocating piston. The cylinders may be placed side-by-side andarranged to be reciprocated by a single operating handle.

The assemblies of the figures may be operated by mechanical orelectromechanical means, if desired. For example, a motor M may drive areciprocating arm A through shaft S which is coupled to handle 11 ofFIG. 1. A rotary to reciprocating motion device D converts the rotationof the shaft S into reciprocating movement. Alternatively, a relay Rhaving a reciprocating armature RA may be alternately energized anddeenergized to reciprocate up and down (for example) to impartreciprocating movement to the piston rod (for example). The down strokemay be imparted by energizing the relay driving its armature downward.Deenergization of relay R will cause the upstroke under control of abiassing spring (not shown).

Although this invention has been described with respect to particularembodiments, it should be understood that many variations andmodifications will now be obvious to those skilled in the art, and,therefore, the scope of this invention is limited not by the specificdisclosure herein, but only by the appended claims.

lclaim:

1. A portable mechanical ventricular assistance device comprising:

a ventricular assistor cup assembly including a rigid cup having aninterior configuration adapted to receive the ventricles of the heart;

a flexible liner mounted within said cup having a first opening forreceiving the ventricles of the heart; a first port positioned at theapex of the cup opposite the first opening, and a second port positionedintermediate the first opening and the first port;

said flexible liner being sealed to the interior surface of said cupalong a first marginal portion adjacent to and surrounding said firstopening and along a second marginal portion adjacent -to and surroundingsaid first opening and along a second marginal portion adjacent to andsurrounding said first ports;

A first-sustained negative pressure conduit having a first end coupledto said first port;

a second pulsed positive and negative pressure line having a first endcoupled to said second port;

reciprocating pump means having first and second outputs each capable ofdeveloping positive and negative pressure pulses during reciprocation ofsaid pump;

said first and second outputs being respectively coupled to the secondends of said first and second conduits;

valve means coupled in said first conduit for coupling only negativepressure pulses to said first port.

2. The device of claim 1 further comprising first and second reliefvalve means connected to said second conduit for limiting the maximumpositive and negative pressure pulses delivered to said second port.

3. The device of claim 1 further comprising first relief valve meanscoupled to said first conduit for limiting the negative pressure pulsesdelivered to said first port to a predetermined threshold level; andsecond one-way valve means for releasing positive pressure pulsesinjected into said first conduit to the atmosphere.

4. The device of claim 1 further comprising a liquid trap coupledbetween said first conduit and said first port for preventing the flowof any liquid toward said pump means.

5. The device of claim 1 wherein said pump means is comprised of acylinder containing a reciprocally mounted doubleacting piston dividingsaid cylinder into first and second chambers;

said first and second outputs communicating respectively with said firstand second chambers.

6. The device of claim 1 wherein said pump means is comprised of acylinder having a collapsible bellows-type wall;

said first and second outputs communicating with the interior of saidcylinder.

7. The device of claim 1 wherein said pump means is comprised of acylinder having a collapsible bellows-type wall;

a barrier wall in said cylinder dividing said cylinder into first andsecond chambers;

said first and second outputs respectively communicating with theinteriors of said first and second chambers.

1. A portable mechanical ventricular assistance device comprising: aventricular assistor cup assembly including a rigid cup having aninterior configuration adapted to receive the ventricles of the heart; aflexible liner mounted within said cup having a first opening forreceiving the ventricles of the heart; a first port positioned at theapex of the cup opposite the first opening, and a second port positionedintermediate the first opening and the first port; said flexible linerbeing sealed to the interior surface of said cup along a first marginalportion adjacent to and surrounding said first opening and along asecond marginal portion adjacent to and surrounding said first openingand along a second marginal portion adjacent to and surrounding saidfirst ports; A first-sustained negative pressure conduit having a firstend coupled to said first port; a second pulsed positive and negativepressure line having a first end coupled to said second port;reciprocating pump means having first and second outputs each capable ofdeveloping positive and negative pressure pulses during reciprocation ofsaid pump; said first and second outputs being respectively coupled tothe second ends of said first and second conduits; valve means coupledin said firSt conduit for coupling only negative pressure pulses to saidfirst port.
 2. The device of claim 1 further comprising first and secondrelief valve means connected to said second conduit for limiting themaximum positive and negative pressure pulses delivered to said secondport.
 3. The device of claim 1 further comprising first relief valvemeans coupled to said first conduit for limiting the negative pressurepulses delivered to said first port to a predetermined threshold level;and second one-way valve means for releasing positive pressure pulsesinjected into said first conduit to the atmosphere.
 4. The device ofclaim 1 further comprising a liquid trap coupled between said firstconduit and said first port for preventing the flow of any liquid towardsaid pump means.
 5. The device of claim 1 wherein said pump means iscomprised of a cylinder containing a reciprocally mounted double-actingpiston dividing said cylinder into first and second chambers; said firstand second outputs communicating respectively with said first and secondchambers.
 6. The device of claim 1 wherein said pump means is comprisedof a cylinder having a collapsible bellows-type wall; said first andsecond outputs communicating with the interior of said cylinder.
 7. Thedevice of claim 1 wherein said pump means is comprised of a cylinderhaving a collapsible bellows-type wall; a barrier wall in said cylinderdividing said cylinder into first and second chambers; said first andsecond outputs respectively communicating with the interiors of saidfirst and second chambers.